• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.414-416
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• 2009

In order to build a transient simulation program for a high thrust liquid rocket engine(LRE), a static performance simulation program for components were made. The components were the thrust chamber (combustion chamber and supersonic nozzle), centrifugal pump (impeller and volute casing), impulse turbine, and flow control devices (control valve and orifice). Simplified mathematical models based on classical thermodynamic and inviscid theories were used to remove complexity and enhance the utility of the program. We examined the results of each program qualitatively for validate each component modeling.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.109-120
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• 2008

An innovative method of changing a centrifugal low specific speed pump performance and pressure fluctuation by applying outlet flaps to impeller exit has been investigated. The outlet blade edge section corresponds to the trailing edge of wing on the circular-cascade, which dominates the pump performance and pressure fluctuation. Computational fluid dynamics (CFD) analysis of the entire impeller and volute casing and an experimental investigation are conducted. The pressure fluctuation and the vibration of the shaft are measured simultaneously. Kurtosis is applied as a dimensionless parameter with which the unevenness of velocity distribution at impeller outlet is indicated. The influence of the flaps on the pressure fluctuation is explained by the kurtosis. This paper presents a theoretical method of predicting the pump performance related to the attachment of a flap at impeller outlet.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.181-186
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• 2010

A numerical study was conducted to predict the performance curve of a canned motor pump for SMART(System Integrated Modular Advanced ReacTor). The study used a computational domain which included not only the pump but also a suction pipe and a volute casing with a discharging pipe in order to simulate an experimental setup. The ANSYS CFX program was utilized to obtain flow characteristics inside the pump as well as the overall pressure rise across the pump operating on- and off-design points. Computed results showed that the performance of the pump at off-design points was much lower than expected. Special attention was made to find the cause of the low performance of the pump operating at low flow rate.

• Journal of Power System Engineering
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• v.3 no.2
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• pp.13-19
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• 1999

The purpose of the present experimental study is to apply multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to high-speed flow region within a domestic boiler circulation pump. Two different kinds of flow rate($27{\ell}/min,\;19{\ell}/min$)are selected as experimental condition. A volute casing and Impeller made of transparent Polycarbonate were made for the easy access of the illumination laser via fiber optical line and cylinder lens assembly to the measuring region. A CCD camera is syncronized with AOM to acquire clear original particle images. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. The instantaneous and time-mean velocity distribution, velocity profile and kinetic energy are represented quantitatively at the full-scale region for the deeper understanding of the unsteady flow characteristics in a commercial circulation pump.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.354-358
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• 2005

The magnitude of the axial force acting on turbopump bearings has a great influence on the operational reliability and service life of a turbopump. In the turbopump under current investigation the cavity vanes are introduced to the pump shroud casing to control the axial thrust of the turbopump. To investigate the effect of the cavity vanes, 3D computational flow analyses for a propellant pump stage including an inducer, impeller, volute and secondary flow passages are performed with and without the vanes. The results show that the cavity vanes are very effective in reducing the magnitude of axial thrust without notable changes on the overall performance of the turbopump.

• The KSFM Journal of Fluid Machinery
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• v.14 no.4
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• pp.5-11
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• 2011

This study investigated on details of flow characteristics in a vaneless diffuser of a compressor with 2-dimensional impeller at various flow rates. Experiment for a low speed compressor model in a water reservoir was performed to analyze the flow field in the vaneless diffuser and volute casing, which was done by PIV measurement. It was also focused on the periodic flow patterns occurring at low flow rate near unstable operating region of the compressor. At low flow rate condition, the flow visualization clearly shows that the flow energy from impeller is highly accumulated at the compressor exit by the blockage effect of a flow damper and consequently the reverse flow occurs in the diffuser.

• Fire Science and Engineering
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• v.33 no.3
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• pp.56-62
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• 2019

This study examined effects of the operating characteristics of a pump according to the rotational speed of a pump and the change in flow rate when a centrifugal pump operates under the following conditions: regulated flow rate, head, rotational speed, and specific speed of 0.7 m/min, 8 m, 1750 rpm, an 182 (m, ㎥/min, rpm), respectively. The pump in the experiment did not have a guide vane and was connected directly to the rim, so that the rotational speed of the volute pump in a spiral or volute casing increased by 100 rpm from 1350 to 1750 rpm. The result of the relationship between the H-Q, L-Q, and 𝜂-Q characteristics and the dimensionless performance characteristics, such as the head coefficient, power coefficient and efficiency were studied. The change in pump performance could be estimated depending on the increase in the number of revolutions. The maximum efficiency of the pump was 52% with 1450 rpm, 0.165 ㎥/min flux, and 4.73 m of lift. The efficiency reached 50% with a maximum of 1750 rpm, 0.183 ㎥/min of flux, and 6.72 m of lift. The efficiency curve on the performance characteristics of the lift versus flux curve became oval not a curve from a quadratic equation that passes through the starting point according to the similarity law of the pump. Finally, when the flux coefficient increased, the power coefficient increased and the lift coefficient decreased. When the flux coefficient was 0.08, the maximum efficiency was 52%. Therefore, the change in flux affects the driving characteristics.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.688-695
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• 2012

The present study represents the effects of boundary condition on the performance of a centrifugal blower at the interference plane between rotational and stationary domains using three dimensional compressible Navier-Stocks equations. Two boundary conditions, frozen-rotor and stage, are compared to analyze the blower performance. Installation angle between the cutoff of a volute casing and a impeller blade is also introduced to evaluate the blower performance and to understand the internal flow inside the blower. Throughout numerical simulation, it is found that the frozen rotor interface method at the interference plane represents well the variations of flow field inside the blower compared to stage interface method. However, pressure has maximum two percent error according to the installation angles while pressure is almost constant for the stage interface method. And stage interface method can relatively well predict the blower performance. Detailed internal flows of the centrifugal blower are compared and analyzed by numerical simulation.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.174-175
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• 2005

The purpose of this study is focused on the analysis of 3D complex flow and performance characteristics of a centrifugal pump with volute casing. The numerical analysis was performed by commercial code CFX-10 according to the variation of flow rate, which is changing from 5.847$m^3$/min to 6.865$m^3$/min. The rated rotational speed of close type impeller is 1750rpm. Turbulence model, k-${\omega}$ SST was selected to guaranty more accurate prediction of flow separation. The ICEM-CFD 10, reliable grid generation software was also adapted to secure high quality grid generation necessary for the reliable numerical simulation. The experimental results such as static head, brake horse power and efficiency of the centrifugal pump were compared with the numerical analysis results. The simulated results are good agreement with the experimental results less 5$%$ error.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.191-199
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• 2014

Effects of design variables on the performance of a double-inlet centrifugal blower have been analyzed based on the three-dimensional flow analysis. Two design variables, blade inlet and outlet angles, are introduced to enhance a blower performance. General analysis code, ANSYS-CFX13, is employed to analyze internal flow and a blower performance. SST turbulence model is employed to estimate the eddy viscosity. Throughout the shape optimization of an impeller at the design flow condition, the blower efficiency and pressure are successfully increased by 4.7 and 1.02 percent compared to reference one. It is noted that separated flow observed near cut-off region can be reduced by optimal design of blade angles, which results in stable flow pattern in the blade passage and increase of a blower performance. The stable flow at the impeller also makes good effects at the outlet of a volute casing.